Our proposal aims to improve the detection of hypertension (HTN) by using the emergency department (ED) visit as a novel opportunity for HTN screening and healthcare referral. In the United States (US), 65 million persons are estimated to have HTN; 31 percent are unaware of their condition. Early detection can lead to earlier initiation of therapy and prevention of heart attack, stroke and renal failure. In 2002, US ED patient visits were estimated at 110 million. Even though in 2001, the CDC estimated 1/3 of these patients had an initial BP greater than 140/90, routine referral is rarely done. The meaning of elevated BPs in the ED is unclear and reassessment and referral practices of ED clinicians are poor. Frequently, elevated BPs in the ED are attributed to pain or anxiety, although no data support this belief. Given the large number of patients seen in EDs daily across the US, and the large number of patients with undetected HTN, the ED is a logical and potentially important site to screen for undetected HTN. We aim 1) to determine the proportion of ED patients with no history of HTN and two or more blood pressure readings greater than140/90 during an ED visit, who demonstrate sustained BP elevations when measured at home during the following week, and 2) to identify the socio-demographic and clinical characteristics (e.g., family history of HTN, pain, anxiety, body mass index) associated with sustained blood pressure elevation when measured at home during the week following the ED visit. Aim 2 is exploratory in nature. Data from this pilot study will be used to help identify potentially important patient characteristics and help guide the power analysis for future research that will adequately explore this aim with a sufficient sample size. We will prospectively enroll 180 subjects in the ED that meet study criteria. During patient enrollment, patients meeting study criteria (two or more ED BPs greater than140/90 and no past medical history of HTN) during an ED visit will be identified and enrolled. Patients will participate in a brief medical interview conducted near the conclusion of their ED visit and be given a home BP monitor to record their BP twice a day for one week. The monitor also automatically stores up to 30 readings. At the end of one week patients will be asked to return the home BP monitor. Upon monitor return, study staff will calculate a mean SBP and DBP (using the stored readings) and prepare a summary report with recommendations for follow-up that will be mailed to the patient. All BP readings will be cleared from the monitor prior to re-use. This project will provide evidence of the meaning of elevated ED BPs and an excellent understanding of the true prevalence of undetected HTN in an ED setting. The project will also begin to explore predictors of undetected HTN and the true association between elevated ED BPs and anxiety and pain. This aim will be fully explored in future work.